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Data Control Language (DCL)

A Data Control Language is a language that has various commands which are used to grant and take
back authority from any database user. Some DCL statements are Grant and Revoke.

Transaction Control Language (TCL)

A Transaction Control Language is a language that has various commands which are used to manage
transactions in the database. These are used to manage the changes made by DML statements.
Some TCL statements are Commit, Savepoint and Rollback.

Apart from these commands, SQL also provides clauses which are extensions of the commands. You
will learn more about clauses later in this book.
MODERN DBMS

NoSQL

It is a DBMS that handles large volume of data that is highly unstructured and unlike traditional
DBMS that work only on predefined tables, it provides a flexible data model and support horizontal
scalability. Thus it is suited for for real time data processing that is the need of the hour.

Cloud Databases

These databases allow benefits of cloud computing platform (like scalability, speed and reduced
costs) along with all the features of traditional DBMS. They support relational as well as non-relational
data models, including unstructured and semi-structured data that does not have its tables clearly
defined.

Recap

A database is defined as an organised collection of data that can be visualised as a container
of information.
Database servers are dedicated computers that can hold the actual databases.
RDBMS is a relational DBMS in which tables are linked to each other by fields.

A relational model can be represented as a table of rows and columns.
SQL is the standard language for managing relational databases and performing various
operations on the data in the tables.

Exercise

A. Tick ( ) the correct option.
1. What is a database?

a. Organised collection of information that cannot be accessed, updated, and managed
b. Collection of data or information without organising
c. Organised collection of data or information that can be accessed, updated, and managed

d. None of these

11
Introduction to DBMS